mirror of https://github.com/lua/lua
89 lines
1.8 KiB
C
89 lines
1.8 KiB
C
/*
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** $Id: lzio.c,v 1.13 2000/06/12 13:52:05 roberto Exp roberto $
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** a generic input stream interface
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** See Copyright Notice in lua.h
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*/
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#include <stdio.h>
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#include <string.h>
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#define LUA_PRIVATE
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#include "lua.h"
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#include "lzio.h"
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/* ----------------------------------------------------- memory buffers --- */
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static int zmfilbuf (ZIO* z) {
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(void)z; /* to avoid warnings */
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return EOZ;
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}
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ZIO* zmopen (ZIO* z, const char* b, size_t size, const char *name) {
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if (b==NULL) return NULL;
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z->n = size;
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z->p = (const unsigned char *)b;
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z->filbuf = zmfilbuf;
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z->u = NULL;
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z->name = name;
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return z;
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}
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/* ------------------------------------------------------------ strings --- */
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ZIO* zsopen (ZIO* z, const char* s, const char *name) {
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if (s==NULL) return NULL;
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return zmopen(z, s, strlen(s), name);
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}
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/* -------------------------------------------------------------- FILEs --- */
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static int zffilbuf (ZIO* z) {
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size_t n;
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if (feof((FILE *)z->u)) return EOZ;
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n = fread(z->buffer, 1, ZBSIZE, (FILE *)z->u);
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if (n==0) return EOZ;
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z->n = n-1;
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z->p = z->buffer;
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return *(z->p++);
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}
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ZIO* zFopen (ZIO* z, FILE* f, const char *name) {
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if (f==NULL) return NULL;
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z->n = 0;
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z->p = z->buffer;
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z->filbuf = zffilbuf;
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z->u = f;
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z->name = name;
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return z;
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}
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/* --------------------------------------------------------------- read --- */
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size_t zread (ZIO *z, void *b, size_t n) {
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while (n) {
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size_t m;
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if (z->n == 0) {
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if (z->filbuf(z) == EOZ)
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return n; /* return number of missing bytes */
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else {
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++z->n; /* filbuf removed first byte; put back it */
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--z->p;
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}
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}
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m = (n <= z->n) ? n : z->n; /* min. between n and z->n */
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memcpy(b, z->p, m);
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z->n -= m;
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z->p += m;
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b = (char *)b + m;
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n -= m;
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}
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return 0;
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}
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